In view of the potentially hazardous nature of many agricultural chemicals such as insecticides, it is desirable to minimize the potential exposure of personnel to such chemicals. European Patent Application No. 0 685 155 discloses a valve device for connecting a container filled with flowable material to an applicator device for dispensing the flowable material. The valve device has a housing connected in use to the outlet of a container of flowable material and a valve member connected to the inlet of a hopper forming part of the applicator device. Relative movement between the housing and the valve member then enables the flowable material to pass from the container to the hopper.
Although valve devices of this type serve to minimize exposure of personnel to the flowable material in question, such devices have hitherto only been used in applications in which the applicator device is mounted to a tractor. However, in many areas of the world, particularly in third world countries, tractor mounted applicator devices are unsuitable. For example, tractors may be unavailable for economic reasons, or unusable for reasons of uneven terrain, or the particular agricultural activity involved, such as on banana plantations where the random growth of banana plants prevents the arrangement of the plants in rows between which a tractor can pass.
In such cases, it is generally the practice to dispense agricultural chemicals from a portable backpack applicator. Such applicators generally have a refillable reservoir for flowable material which is filled from a (usually larger) container or bag of flowable material. However, in many third world countries, there is the potential hazard of the empty container being re-used in an unsuitable manner, such as the storage of drinking water or, especially in the case of bags, the hazard of disposal by incineration with the accompanying environmental hazards.